A drone flew over a French prison, reportedly delivering a mysterious parcel intended for some of the inmates. Prison guards seized the drone but were unable to retrieve the contents of the package.

The incident took place in the Penitentiary Center of Valencia on Tuesday. The drone was equipped with a camera that allowed the unidentified perpetrator to navigate the UAV around the prison, according to France Bleu.

As the drone reached the courtyard where the majority of inmates were present at the time, it managed to avoid getting stuck in the safety net that is supposed to help keep foreign objects out of the prison.Guards seized the drone but not before the inmates managed to grab and hide the contents of the parcel.

An investigation is currently underway, with the police working to identify the perpetrators and the package’s whereabouts.